GENERAL DESCRIPTION

The CM6802 is a green PFC/PWM. It is the new generation of ML4802, ML4841, ML4801 and ML4824-2. Its system clock frequency is generated by the external RT and CT, and then its PWM frequency is 50% of the clock and its PFC frequency is 25% of the clock. CM6802 is designed to

be pin-pin compatible with CM6800 family, ML4800 family and ML4824 family. Its PWM (DC to DC section) can be easily configured to Voltage Mode or Current Mode.   The green mode function can easily be designed so during the no load condition, its input power can be less than 0.75Watt

without shutting off PFC. Its PFC green mode threshold and the PWM green mode threshold can separately set by selecting the proper the RC filter at ISENSE pin (pin3) and CT on RAMP 1 pin (pin 7). Power Factor Correction (PFC) allows the use of smaller, lower cost bulk capacitors,

reduces power line loading and stress on the switching FETs, and results in a power supply that fully compiles with IEC-1000-3-2 specifications. Intended as a BiCMOS version of the industry-standard CM6800, CM6802 includes circuits for the implementation of leading edge, average

current, “boost” type power factor correction and a trailing edge, pulse width modulator (PWM). Both PFC and PWM Gate-driver with 0.5A capabilities minimizes the need for external driver circuits. Low power requirements improve efficiency and reduce component costs.

FEATURES

Patent Number #5,565,761, #5,747,977, #5,742,151, #5,804,950, #5,798,635

fosc=2 x fpwm =4 x fpfc

No bleed resistor required

Before the chip wakes up, IAC can start up VCC

Pin to pin Compatible with CM6800, ML4824 and ML4800 (It needs to modify the values of the external component to work properly).

User Program PFC automatic green mode threshold(patented)

User Program PWM automatic green mode threshold(patented)

Input power less than 0.75Watt without shutting off PFC at no load condition.

Additional folded-back current limit for PWM section.

23V Bi-CMOS process

PWM pulse keeping for the green mode

VIN OK guaranteed turn on PWM at 2.5V instead of 1.5V 

Internally synchronized leading edge PFC and trailing edge PWM in one IC

Slew rate enhanced transconductance error amplifier for ultra-fast PFC response

Low start-up current (30µA typ.)

Low operating current (3.0mA type.)

Low total harmonic distortion, high PF

Reduces ripple current in the storage capacitor between the PFC and PWM sections

Average current, continuous or discontinuous boost leading edge PFC

VCC OVP Comparator will turn off both PFC and PWM

Low Power Detect Comparator

Tri-Fault detect to meet UL1950

PWM configurable for current mode or voltage mode operation

Current fed gain modulator for improved noise immunity

Brown-out control, over-voltage protection, UVLO, and soft start, and Reference OK

APPLICATIONS

Desktop PC Power Supply

Internet Server Power Supply

IPC Power Supply

UPS

Battery Charger

DC Motor Power Supply

Monitor Power Supply

Telecom System Power Supply

Distributed Power